Fusible element



May 11. 1927.

DE 1.05 N. HICOK FUSIBLE ELEMENT Filed Aug. 17, 1922 gvwemtoz [7510a A! Moo/f Patented May 17, 1927.

UNITED STATES PATENT OFFICE- DE LOS HICOK, OF NEWARK, NEW JERSEY, ASSIGNOR TO FEDERATED. ENGINEERS.

DEVELOPMENT CORPORATION, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF DELAWARE.

FUSIBLE ELEMENT.

This invention relates to improvements in fusible elements such 'as the temperature sensitive element commonly used to control sprinkler systems or similar devices.

In order to more fully understand the objectsof the present invention, it will be necessary to point out certain of the defects of the fusible elements or links now commonly employed which consist of various metallic alloys. In the first place, a fusible alloy to melt at a definite temperature throughout its entire mass must be what is commonly known as eutectic. This corresponds with a definite but not usually with a simple proportion of the metals. Owing to the oxidation and drossing of these metals during the process of alloying, it is hard to hold even a binary alloy to a definite composition and almost impossible to keep a ternary or quaternary alloy homogeneous and of definite proportion.

As a consequence, these fusible alloys are not reliable. While the eutectic alloys will theoretically melt at a definite temperature, as a matter of fact the commercial alloys vary from the eutectic and are liableto melt asmuch as10 F. above or below the theoretical temperature; again the remelting of the alloys in casting will often make a radical change in the composition and a serious variation in the melting point.

Furthermore, fusible metallic alloys have virtually no power of resisting a prolonged stress. They are more or less ductile or plastic even at ordinary temperatures and if subjected to loads of pressure or tension, even if the loads are light, will, in the course of time, flow or yield to the load even while cold. In other words, all these alloys are in reality viscous fluids even at normal temperatures and their fluidity or plasticity increases greatly as they are heated. They become so soft --at temperatures far below theirmelting point, that when a power transmitting element is connected to them, they Will gradually yield, twist or stretch and eventually rupture at temperatures widely variant from. their calculated; melting or yielding point.

Furthermore, fusible alloys are limited to a few eutectic alloys of narrow temperature range. They'are subject to corrosion by certain chemicals and fumes such as nitric and chlorine, and cease to function when so attacked.

I I am aware that other fusible substances besides metallic alloys have been employed as fusible elements, such as arafline, resin, sealing wax, pitch, etc. Siich substances are very unsatisfactory for the reason that they are very plastic when heated and will yield at temperatures that are far below their melting points.

An objectof the present invention is to provide a fusible element which will remain solid and unyielding even when heated up to a temperature closely approaching its melting point; in other words, to provide an element whose elastic limit is'close to its rupture point even when heated approximately to its melting point so that the element will not yield until it ruptures or is about to rupture; or in still other words, to employ an element that does not pass througha wide range of plasticity as its temperature is raised to its melting point? Another ob'ect is to provide an element capable ofwlthstanding tension, compression or torsion and an element whose melting point or point of release will be absolutely definite within 1 or at the most 2 F In other words, I propose to supplant the metallic alloys and other fusible materials heretofore used, all of which are more or less ductile or plastic even at temperatures far below their melting points and which will flow and stretch readily as they approach within ten or fifteen degrees Fahrenheit of their melting point, by a homogeneous crystalline substance which is nonplastic and which remains unyielding until it is heated to a. certain temperature when it will suddenly liquefy or rupture. It is a further object of this invention to supply fusible 'elements that may be used at temperatures below those possible with fusible alloys, such as freezing mixtures; also to cover a wider range of temperature than is possible to do with fusible alloys. I It is yet another object of this invention to suggest certain constructions of links or certain combinations of my fusible elements with a surrounding or supporting 001113311181 which may have various uses.

With these and otherob ects in View, the invention consists in certain novel features of construction. and combinations and arrangement of parts as will be more fully hereinafter described and pointed out in the claims.

In the accompanying drawings, Figure 1 is a somewhat diagrammatic sectional view illustrating the type of link or- .fusible element which I prefer to employ points have proven to be most satisfactory requirements may purposes because of the difference in their 'melting points. Alpha-mono-nitronaphthafor fulfilling the objects hereinbefore stated. An organic compound is preferred, preferably-but not necessarily, an organic salt. The nature of the compound depends obviously upon the use to which-it is to be put, since compounds having (the necessary be utilized for different lene, for instance, will be found desirable for indicatin temperatures of approximately 120 F. ichlorbenzene, diphenylamine and various other pure chemical compounds may be used when adifi'erent melting point is desired.

It is a well known fact that many pure staple chemical compounds of crystalline character, have an elastic limit near their point of rupture, will melt throughout their mass within 1 or 2 of temperature, and being of a fixed definite composition will melt and solidify an indefinite number of times without change of character.

It is also a well known factthat many such compounds are known that heretofore have found little commercial application. Again the melting point of a compound may be changed by the addition of one or more radicals, the substitution of one or more radicals or change in orientationof one or more radicals. Furthermore, the resistance to corrosion, solution, etcimay be changed by similar processes.

It is a, purpose of this invention to utilize these characteristics of pure stable chemical compounds as a nieans of obtaining fusible elements, that will cover wide ranges of temperatures, that will be reliable and .permanent, and can be adjustedto resist specific causes of corrosion and deterioration.

It has been heretofore suggested that suitable substances might be-found for Withstanding the action of acid fumes. In the event that a link is to be used in an atmos- I phere containing chlorine gasg a link of some substance such as dichlorbenzene might be used. Cobalt nitrate or dinitrobenzene Would serve a similar purpose in the event that nitric acid was in the air. Still another method of accomplishing the same result would be to coat the entire link by dipping in a chemical compound resistant to specific surroundings. This construction serves to provide a protecting coating of anotherpure stable chemical compound of a higher melting point to resist the action of the surrounding medium. Links of different types would of course be used to resist the actionof different gases, acids, alkalis and chemicals.

Referring with particularity to Figure 1 of the drawings, I have used the reference numeral 1 to indicate a cup-like container into which a pre-heated pure chemical compound 7 may be poured in a liquid state. As the compound solidifies, it serves to embed within itself one end of a link 2 of a chain. An inturned lip 3 at the upper end of the cup-like container prevents the entire body of compound from being pulled out of its casing when tension is exerted on the chain 4 of which the link 2 forms a part. I have designated a contraction spring 5 actingto tension the chain and have shown the container l as formed with a depending apertured lug 6 receptive of a chain link. With this form of device, the chemical compound will melt or release whenever the temperature of the heat conducting casing 1 reaches the necessary point. The compound, however, is absolutely prohibitive of any yielding or stretching of the chain prior to the time such temperature is reached. l

,Referring in detail to Figure 2 of the drawings, I have illustrated a container 10 adapted to seat on a supporting base 11. A, connecting rod 12 has one end embedded in the chemical compound 13 with which the container 1Q isfilled. An expansion spring 15 is indicated interposed between a suitable support 16 and a ring 17 on the connecting rod. This drawing is merely illustrative of the fact that a chemical compound such as set forth in the claims will not yield under compression prior to reaching its melting point or point of release.

In the modified form of device shown in Figure 3, a casing 20 for the fusible mate rial 21 is formed with a stuffing box 22 in ly to stop its operation whenever the tem through the medium of a pulley Wheel 28 on the upper end of said shaft. Radially disposed blades or paddles 29 secured to the shaft and embedded in the compound serve to absolutely prevent any turning movement of the shaft independent of the container.

As soon as the temperature of the compound reaches the necessary point, the same will liquefy permitting turning of the pulley. and revolution of the paddle blades. This form of the invention is not only useful in retaining a mechanical device against premature operation, but may be used converseperature of the compound becomes sulficiently low to solidify the same. In cases,

for instance, Where it is desirable to maintain a boiling mixture at a pre-determined point, the paddle blades would be suddenly stopped, their stoppage acting to operate a signal in any approved manner to indicate a falling temperature.

To sum up, it Will be seen that I provide a link or similar fusible device comprising a container adapted to be filled with a chemical compound. A mechanical device embedded in the compound and placed under ten- 'sion, compression or torsion will be held against motion as long as the compound remains in a solid state. When the temperature of the material surrounding the compound rises sufliciently to cause melting of the compound, said mechanical device is re-.

leased and set in motion. The device may be used to indicate temperature, to operate a signal, to open or close a valve, empty or fill a tank, or in other ways too numerous to mention.

It'will be understood that the word element as used in the foregoin specification and the appended claims is to he interpreted not in its technical chemical sense but in its general sense as meaning an essential part, body, member or substance.

I have illustrated certain of the preferred embodiments of the invention and have specified a few stable chemical compounds suitable for the purpose of carrying it out, but it will be evident that I do not wish to be limited to any class of compounds, ex-

cept as defined in the appended claims.

I claim:

1. As a new article ,of manufacture, a temperature sensitive device comprising a liquid container adapted to receive a fusible substance in liquid state, a fusible substance therein consisting of a stable organic compound of crystalline character, and a stressed element anchored in the compound.

2. As a new article of manufacture, a

temperature, sensitive device comprising a liquid container adapted to receive a fusible substance in liquid state, a fusible substance therein consisting of a stable organic salt, and a stressed element anchored in the compound. a

3. As a new article of manufacture, a temperature sensitive device comprising a liquid container adapted to receive a fusible substance in a liquid state, a fusible. substance therein consisting of a st ble, chemical compound of crystalline char cter, and a potential element anchored in said compound. j

4. As a new article of manufacture, a temperature sensitive device comprising a liquid container adapted to receive a fusible substance in a liquid st'ate,-a fusible substance therein. consisting of a stable chemical compound of definite melting point, and a stressed element anchored in said compound.

5. As a new article of manufacture, a temperature sensitive device comprising a liquid container adapted to receive a fusible substance in a liquid state, a fusible substance therein consisting of a stable chemical compound having its rupture point and elas- 7. A temperature sensitive device compris;

ing a pair of relatively stressed members and a body of fusible material serving while solid, to hold said members against relative movement, said body consisting of a stablechemical compound of crystalline character.

8. A temperature sensitive device comrisin a air of relativel stressed members and a body of fusible material serving while solid, to hold said members against relative movement, said body consisting of a stable organic salt. I

9. A temperature sensitive device comprising a pair of relatively stressed members and a body of fusible material serving while solid, to hold said members against relative movement, said body consisting of a stable chemical compound of definite melting point. I

10. A temperature sensitive device comprising a pair of relatively stressed members and a body of fusible material serving while solid, to hold said members against relative movement, said body consisting of a substance that remains non-ductile at temperatures below and up to its .fusing point.

11. A temperature sensitive device comprising a pair of relativelystressed members and a body of fusible material serving while solid, to hold said members against relative movement, said body consisting of a substance that remains non-plastic at temperatures below and up to its fusing point;

12. A temperature sensitive device comprising a pair of relatively stressed members and a body of fusible material serving while solid, to sold said members against relative movement, said body consisting of a sub vicinity of its fusion point.

stance having its rupture point and elastic limit approximately co-incidental at temperatures below and up to the immediate 13. A temperature sensitive device com prising apair of relatively stressed members and a body of fusible material serving while solid, to hold 'saidmembers againstrelative movement, said body consisting of a stable chemical compound of crystalline character having its rupture point and elastic limit approximately co-incidental at temperatures below and up to the immediate vicinity of its fusion point.

14. A temperature sensitive device 'comprising a pair of relatively stressed members and a body of fusible material serving while solid, to hold said members against relative movement, said body consisting of a stable organic salt having its rupture point and elastic limit approximately co-incidental at temperatures below and up to the immediate vicinity of its fusion point.

DE LOS N. HICOK. 

